I'm a senior physics and mathematics major at Tarleton State University with an interest in public policy. Recently I've noticed that many of my peers, even those who are otherwise very well informed, are in confident denial of the validity of global warming. The trend seems to be that those who understand the concept the least are those who deny it the most fervently.
A functioning democratic government requires that its citizens be well informed, as we elect officials to enforce legislation that we support (at least ideally); it's for this reason that I feel obligated to vocally encourage curiosity and scepticism concerning this issue, to break the evident trend of widespread unawareness concerning the details so that more efficient and less damaging methods of electricity generation are adopted.
The current state of scientific consensus, based on definitive measurements of the global mean surface temperature and the application of some basic principles of science and mathematics, is that the increased concentration of greenhouse gases (particularly carbon dioxide, the levels of which have risen significantly during the industrial revolution and which are linked directly to human activity has unequivocally led to an increase in the global surface temperature in a fashion that cannot be accounted for by natural means alone.
While gradual (the average temperature rising only about a degree Fahrenheit between the years 1901 and 2000, leading to noticeable changes in global sea and ice levels), the continued effects are confidently predicted to include extreme alterations in weather and agricultural patterns, alongside the perhaps irrevocable unfavourable modification of our atmosphere.
The basic science behind global warming is easy enough to understand. It hinges on the greenhouse effect: the earth absorbs radiation from the sun, and in turn the earth re-emits radiation in the form of heat back into space; a percentage of this heat, however, is absorbed by the greenhouse gases in the atmosphere, some of which is reflected back onto the earth's surface, continuing the cycle. (This is a simplified model — in reality the process is more complex, but the overall effects that we're concerned with are unchanged.) As humans burn fossil fuels, carbon dioxide is released and collects in the atmosphere, thus increasing the concentration of greenhouse gases. This leads to a raised amount of heat being trapped in the earth's surface and lower atmosphere, leading to an increase in average global surface temperature.
Thus, those who deny mankind's involvement in global warming must refute the laws of physics; but while they are working on that, let us take steps to prevent further damage to our planet, and to become sceptical enough to seek out facts before forming opinions.